Grinding compound



Patented June 17, 1924.

human STATES PATENT ounce.

GEORGE W. BENEDICT, F

MINNEAPOLIS, MrnNEsorA, assrenon, BY mEsnE ASSIGN- MENTS, TO WOOD-IMIESMANUFACTURING COMPANY, Oi MINNEAPOLIS, MINNE- SOTA, A CORPORATION OFSOUTH DAKOTA.

GRINDING COMPOUND.

Ho Drawing.

To all whom it may concern:

Be it known that I, GEORGE W. BENEDICT, a citizen of the United States,resident of Minneapolis, in the county of Hennepin 6 and StateofMinnesota, have invented certain new and useful Improvements in GrindingCompounds, of which the following is a specification.

This invention relates to improvements in W abrasiveor grindingcompounds adapted to grind and finish the surface of metals. It is moreparticularly adapted for use in fitting, truing and removing the highspots from istons, cylinders, valves, valve seats and 0t or moving partsof engines and machinery.

Heretofore grinding compounds have consisted mainly of carborundum,emery, ground glass, and other abrasives of a relatively permanentlyabrasive nature. Such compounds 1y indefinite period and in using thesecompounds it is difficult, if not in the majority of cases impossible,to remove the compound after the proper grinding function is achieved;The carborundum', emery, ground lass or similar substance apparentlyworks its way into the metal or about the part being treated andcontinues to grind after the proper fitting of the moving parts.Detrimental results obviously follow. Furthermore, as these substancesare not thoroughly removed, they are apt to cause freezing of theworking parts and scoring (as for exam le of engine cylinders), due tocontinue abrasive action and resultant friction. Likewise, the presenceof such abrasive in a machine or engine is apt damage the parts betweenwhich there is movement. This novel compound is composed of an abrasivematerial which loses its 1 abrasive efi'ect and becomes smooth in arelatively short time during use on hard metals, such as cast-ironaluminum, lynite, magnolite, semi-steel, steel, and bronze. It is notintended for use on Babbitt metal. The selected abrasive materiak aresufiicientl hard and sharp to provide the desired grincl in so sir edquantity of material may be em loyed to effect the correct grinding witht e asbecome smooth after a relativemixture to stand for action for ashort period and the de- Application filed April 24,1922. Serial No.556,330.

surance that the material will relatively rapidly become non-abrasiveafter its purpose has-been achieved. Thus, for example, in fitting andtruing working parts of enines and machinery the above-mentioned ighspots may be removed and grinding action beyond the necessary pointproperly to fit the parts is prevented. Furthermore the novel compoundis such that it may be rendered practically non-abrasive by use oflubricating oil.

The object therefore of this invention is to provide an improvedgrinding compound.

Other objects of the invention will more 7 fully appear from thefollowing description and will be pointed out in the annexed claims. I

The principal ingredient of this novel grinding compound is the abrasivematerial and this material must have the attribute of relatively rapidlylosing its abrasive property when used on hard surfaces. A

silica-like material 'presents the desired characteristics and thepreferred silica-like ma- 1 terial is quartz. A uniform grade of quartzparticularly adapted for the purposes of this compound may be obtainedfrom the well-known quartz quarries in Indiana.

, The quartz is preferably employed in a finely divided state, beingground to pass a 140 mesh screen so that the piu-ticlesawill be fine,uniform and substantia y-free from foreign matter yet gritty and sharp.

A fluid is added to the ground quartz so that the mass is converted to asubstantially viscous mass. The fluid employed is preferably one whichexercises a cleansing efi'ect upon the surface being treated. Theselected cleansing fluid must be substantially without lubricatingqualities in order not to interfere with the abrasive function of theground quartz. While a saponaceous liquid may be emplo ed for thispurpose, it is preferable to use cleansing properties but little or nolubricatingqualities. It is to be noted that the best results areobtained by permitting the 36 to 48 hours and screening and stirringabout once every 12 hours.

Preferably a body element or filler is em erosene or similar oils havingployed to overcome any tendency of the ground quartz and kerosene toform a coagulant mass. There are many organic substances suitable forthis purpose such as wood powder, saw-dust, wool, peat, etc., in afinely divided state. However, it is found that ordinary egg-shellsprovide a ood filler to prevent coagulation. These s ells are crushedand so mixed with the quartz and kerosene. If used, the filler is addedbe.- fore the settin and stirring.

The proportions of the above-mentioned ingredients are such that thequartz predominates. Where ground quartz and kerosene are employed thepreferred proportions are 150 pounds of quartz ground to 140 mesh to I10 gallons of kerosene. If the filler be employed and egg-shells are theselected filler, then 30 pounds of egg-shells are used with theabove-mentioned proportions of quartz and kerosene,

As above noted the com ound is preferably used in a substantiallyviscous form with the'egg-shells functioning to overcome any tendency,to coagulation of the quartz and kerosene while the latter provides thedesirable working consistency. and also provides the means for cleansingthe surface being abraded by the compound. The eggshells also have avery slight abrading action in the nature of burnishing.

It has been found desirable to provide the compound with an odorousingredient to predominate'over the smell of the kerosene. Therefore, anoil obtained'from green cedar leaves is used. This oil overcomes thesmell of the kerosene and has little or no lubricat-.

ing qualities. However, it is to be understood. that other odoroussubstances may be employed in place of the odorant mentioned.-

When added to the compound prepared according to the above-mentionedproportions, about one-half pound' of this selected odorous oil is used.

In preparing the compound in the pre-- ferred proportions abovespecified, the filler, if used, is first mixed with the ground quartz,then such mixture is sifted into the kerosene, and the resultantsemi-fluid mass is set, screened and stirred, as above-mentioned. If theodorous oilbe used, itisadded last.

In using the compound, it is'placed upon the surface to be ground andthe compound is suitably pressed thereagainst, or the compound is placedbetween the co-operative surfaces to be treated and one of the bodiespresenting such surfaces is moved while forcibly held against the other.The'particles of the abrasive ingredient of the compound being hard andsharp will quickly perform their abrading function and, from the natureof the preferred abrasive, will relatively rapidly lose their abradingproperty and will become substantially smooth and non-abrading and evenif particles are process for fitting pistons to cylinders. The

present grinding compounds containing carborundum or emery aredisadvantageous for this work due to the fact that particles of suchhard abrasives are difiicult to remove completely from the cylinders andthe abrading continues when the pistons and cylinders are put in useafter the grinding is supposedly completed. In the present compounds,the particles of the abrasive material break or are crushed or ground bythe abrading action into smaller hard sharp particles with new abradingpoints, edges or surfaces with the result thatthe abrading functioncontinues relatively indefinitely.

.In the novel compound, the particles of the abrasive material do notbreak into smaller particles with renewed abrasive properties.

The size of the abrasive particles of this .novel compound will governto a great extent the clearance thereby obtained in lap ping-in pistons.The 140 mesh compound is particularly adapted for lapping-in pistons forautomobiles. Thus, such sized compound will give the 2-1000th clearanceusual in this work. The compound is poured upon a piston in its cylinderand the piston is vertically reciprocated and turned-until the pistonwill drop under its own weight vertically through the cylinder while thecompound is on the cooperative faces of the piston. The cutting life ofeach particle of this novel com ound is substantially definite. Forexample, 1f .the interior wall of a castiron cylinder be burnished bymeans of a sizing tool exerting a pressure upon the wall of 15 poundspersquare inch, the particles of the compound above set forth will have acutting life of 16 inches of travel upon the cast-iron walls. In otherwords the abrasive particles are worn smooth and their effective cuttingfunction ceases. While several applications of this novel grindingcompound are necessary in carrying out such lappingin process becausethe abrasive effect of each application relatively rapidly deteriorates,such disadvantages greatly overbalancedby the fact that even the dulledparticles of the silica-like abrasive ingredient may be completelyremoved by the application of any of the common lubricating oils. Theabrasive ingredient of this improved grinding compound eliminates thebad effect of the hard abrasives, such as carborundum, emery,

etc., working into the metal surface treated.

by the use of lubricating oil.

I claim as my invention:

1. A grinding compound composed of finely divided quartz, kerosene inproportion 'to form a substantially viscous mass,

and a filler proportionately added to prevent coagulation.

2. A grinding compound for metallic surfaces composed of finely dividedquartz, a liquid having cleansing properties and substantiallynegligible lubricating properties, said liquid being proportionatelyadded to roduce a substantially viscous mass, and a hllerproportionately added to prevent ooagulation.

3. A grinding compound composed of ground quartz, kerosene, cedar oiland ground egg-shells in the proportions of pounds of quartz to 10gallons of kerosene, pound of cedar oil and 5 pounds of eg shells.

In witness whereof, I have hereunto set my hand this 12th da of April,1922. GEOR E W. BENEDICT.

